Some things have been commonplace for too long. Times are changing, and some of it is for the best. There probably aren't too many people out there faced with the question of having a three- or four-speed automatic in their truck who would opt for three, but again, there might not be too many people who have thought about it. The 4L60 transmission has been around long enough to prove itself, and it is a shoe-in to replace a Turbo 350 or 400, plus it can be found in a non-electronic controlled version that'll work behind a Chevy motor in almost any old truck. Cruising down the freeway while floating the valves keeping up with traffic isn't much fun, and that fourth gear sure would be nice.
Gear Star is a company that's been around for over 20 years in the custom-built transmission business, and it is a firm believer in the 4L60 as a workhorse that'll take a floggin' and keep on joggin'. The 4L60 also has an electric fourth-gear lockup that totally eliminates any slippage in the torque converter and results in a 30-percent overdrive ratio via the lockup's mechanical connection to the motor, which will also help the tranny stay cool and lubricated for long periods on the road. All of this is a benefit of a trans that'll withstand up to 700 horsepower thanks in part to a super-streetable Yank Racing 10-inch converter that behaves like the best 12-inch converter off the line, but can take all the abuse your foot can dish out.
Gear Star transmissions are built to order by one of a few master mechanics with over 20 years under their belt; they don't have an "off the shelf" package. That same guy tears down, pulls the parts, builds, and dyno's each tranny. Their Level 3 transmissions have many of their own upgraded parts, such as output shafts five times stronger than stock thanks to the 300M hardened steel many of their parts are made from. Once this sucker is in you won't break it or worry about it. According to Gear Star's Zack Farah, each comes with a 4-month/24,000-mile warranty to back it up.
Replacing the old TH400 with Gear Star's Level 3 4L60 in a '72 Chevy C-10 was basic, but care needs to be taken while adjusting the TV cable to ensure the right change in line pressure inside the tranny to coincide with how much your foot is on the gas pedal. Your driveshaft might have to be shortened like ours was by local shop O.C. Driveline or a new one made depending on the application and if it's a one- or two-piece unit. We also opted for a new tranny crossmember from Performance Online that makes for more room between the frame-rails thanks to its simple yet effective design.
Your motor, wallet, and ears will thank you in the end. With the lower cruising rpm, just try to keep your hot foot cool. Check the source box to contact these companies for more info.